Phenol is ortho-para directing such that the alkylation of phenol gives a mixture of ortho- and para-alkylphenols. In some applications a meta-alkylphenol is needed. For example, Eur. Pat. Appl. 173,993 (Chem. Abst. 105, 60432, 1986) describes the use of meta-tert-butylphenol as an intermediate for a rice herbicide.
One obstacle in the way of developing an efficient process for making meta-alkylphenols is that this isomer is almost impossible to separate from the para isomer by distillation as both have about the same boiling point. Accordingly a need exists for a process for making meta-alkyl phenols free of para-alkylphenols.
Bottini et al., J. Am. Chem. Soc. 79 1458 (1957) reported the reaction of ortho-chlorotoluene with sodium hydroxide to yield a mixture of ortho- and meta-cresol in approximately equal amounts.